浓硫酸低温分解混合稀土精矿动力学分析  

Kinetic Analysis of Decomposition of Mixed Rare Earth Concentrate with Sulfuric Acid at Low Temperature

作　　者：王少炳 李解[1] 李保卫[1] 韩继铖[1] 王介良[1] 李成元[1] 

机构地区：[1]内蒙古科技大学白云鄂博矿多金属资源综合利用国家重点实验室,内蒙古包头014010

出　　处：《稀土》2015年第4期31-37,共7页Chinese Rare Earths

基　　金：内蒙古自然科学基金项目(2012MS0714);内蒙古自治区科技创新引导奖励基金项目(20111624);白云鄂博矿多金属资源综合利用国家重点实验室资助项目(BO-13-001);内蒙古科技大学产学研合作培育基金(PY-201220)

摘　　要：基于热重-差热实验数据,采用Freeman-Carroll微分法、Achar-Brindley-Sharp-Wendworth微分法和一般积分法三种方法,全面分析了硫酸分解稀土精矿的反应动力学行为,推断其反应机理,计算反应表观活化能、反应级数、频率因子等动力学参数,确定不同温度段反应的限制性环节。结果显示,浓硫酸低温分解混合稀土精矿在阶段Ⅰ（160℃--220℃）和阶段Ⅱ（310℃~340℃）两个温度阶段的反应比较剧烈。由Freeman-Carroll微分法计算得到阶段Ⅰ反应的表观活化能E为33.02 k J·mol-1、反应级数n为0.51;而阶段Ⅱ的表现活化能E为182.75 k J·mol-1、反应级数n为0.61。同时,由Achar-Brindley-Sharp-Wendworth微分法和一般积分法计算得到阶段Ⅰ反应的表观活化能E分别为34.66 k J·mol-1和38.36 k J·mol-1,机理函数分别为f（α）=（1-α）和G（α）=[-ln（1-α）]3/2;而阶段Ⅱ反应的表现活化能E分别为215.23 k J·mol-1和205.46 k J·mol-1,机理函数分别为f（α）=2（1-α）[-ln（1-α）]1/2和G（α）=[-ln（1-α）]3/2,两种方法确定的反应限制性环节均为随机成核和随后生长的化学反应,且与Freeman-Carroll法的表观活化能计算结果相近。Based on the experimental data of TG - DTA, reaction kinetics behavior of decomposition of rare earth concen- trate with sulfuric acid was comprehensively analyzed by three methods such as Freeman - Carroll differential method, Achar - Brindley- Sharp- Wendworth differential method and General integral method. The reaction mechanism was inferred, the re- action kinetic parameters such as apparent activation energy,reaction order, frequency factor were calculated and control link was determined in different heating - up period of acid leaching reaction. The results showed that the react of mixed rare earth concentrate with concentrated sulfuric acid was violent at low temperature in two temperature stages of I （ 160 ~C - 220 ~C ） and II （310 ~C -340 ~C ）. The apparent activation energy （E） was 33.02 kJ ~ tool-1 and reaction order （n） was 0.51 in stage I ; E was 182.75 kJ ·mol -1 and n was 0.61 in stage II from Freeman - Carroll differential method. By Achar - Brindley - Sharp - Wendworth differential method and General Integral method, the apparent activation energies （E） were 34.66 kJ·mol - 1 and 38.36 kJ ·mol - 1 and mechanism functions were f（α） = （ 1 - α） and G （α） = [ - In （ 1 -α） ] 3/2 respectively in stage I; E were 215.23 kJ ·mol-1 and 205.46 kJ·mol- 1 and mechanism functions were f（α） = 2 （ 1 - α）[- In （ 1 - α） ] 1/2 and G（α） = [ -In（ 1 -α） ] 3/l respectively in stage II. The control links determined by two kinds of methods were both the chemical reaction control of stochastic coring and afterward growing up, and the calculation results of activation energy were similar with that by Freeman - Carroll method.

关 键 词：稀土精矿 低温分解 硫酸 反应动力学 

分 类 号：F845[经济管理—保险]